ISPconfig web interface

Hi guys,
i have a multiserver setup that consists from 2 nodes: web and mail. Due to my internal reasons i need to split them. But web interface only installed on WEB node. is any option/chance to install web interface on mail node as well without harming current setup (i mean that i dont want to break mail server configuration).
Also, how i can safely remove node from managing by other node, so both of them can action like a standalone servers.